The underlined section is referred to as a(n)
couplet
iamb.
pentameter.
quatrain.

A quatrain.

Explanation: A quatrain is composed of four lines, while a couplet has only two, and an iamb is made up of a pair of syllables (meaning two syllables), with the first being unstressed and the second being stressed. The underlined section is composed of four lines, and the only tern fitting that description would be "quatrain".

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the continental shift will thus cause him to age 2x the speed of light, resulting in a chair the size of an atom.